The present application claims the priority of the commonly owned copending German patent application Serial No. 100 06 372.1 filed Feb. 12, 2000. The disclosure of the above-referenced German patent application, as well as that of each US and foreign patent and patent application identified in the specification of the present application, is incorporated herein by reference.
The present invention relates to improvements in so-called rod making machines, and more particularly to improvements in methods of and apparatus for treating tows, streams, fillers and similar accumulations of filamentary material in such machines.
Rod making machines are utilized extensively in many branches of industry, for example, in connection with the making of catamenial tampons, in connection with the making of drinking straws and particularly in connection with the making of plain or filter cigarettes, cigars, cigarillos and other rod-shaped smokers"" products. The following passages of this specification will deal primarily with the making of filter cigarettes, cigars or cigarillos; however it is to be understood that the method and apparatus of the present invention can also be practiced and utilized in connection with the making of numerous other types of rod-shaped products which contain a single type or several types of filamentary material.
A rod making machine which is utilized to turn out filter mouthpieces for tobacco smoke is normally designed to process filamentary filter material (such as cellulose acetate fibers) for tobacco smoke. The machine produces a continuous filter rod wherein a rod-shaped core (called filler) is surrounded by a tubular envelope or wrapper of so-called filter paper. The rod is advanced lengthwise and its front end portion is severed at required intervals to form a file of discrete filter sections or mouthpieces of unit length or multiple unit length. Such mouthpieces are fed into the magazine of a so-called filter tipping machine wherein the mouthpieces are connected with plain cigarettes, cigars or cigarillos (hereinafter referred to as plain cigarettes) to form therewith filter cigarettes of unit length or multiple unit length. Reference may be had, for example, to commonly owned U.S. Pat. No. 5,135,008 granted Aug. 4, 1992 to Oesterling et al. for xe2x80x9cMETHOD OF AND APPARATUS FOR MAKING FILTER CIGARETTESxe2x80x9d.
Filter rod making machines which deliver filter rod sections or mouthpieces of desired length to a machine of the type described and illustrated in the patent to Oesterling et al. (or to an analogous machine) can be constructed and assembled in a manner as disclosed, for example, in U.S. Pat. No. 3,974,007 granted Aug. 10, 1976 to Greve for xe2x80x9cMETHOD AND APPARATUS FOR THE PRODUCTION OF FILTER ROD SECTIONS OR THE LIKExe2x80x9d and in U.S. Pat. No. 4,412,505 granted Nov. 1, 1983 to Hxc3xa4usler et al. for xe2x80x9cAPPARATUS FOR APPLYING ATOMIZED LIQUID TO A RUNNING LAYER OF FILAMENTARY MATERIAL OR THE LIKExe2x80x9d. More recent versions of filter rod making machines of the type described and shown in the U.S. patents to Greve and Hxc3xa4usler et al. are those known as KDF 1, KDF 2 and KDF 3; such machines are distributed by the assignee of the present application. Machines which are utilized to furnish filamentary filter material for tobacco smoke to filter rod making machines can be of the type known as AF 1, AF 2 and AF 3 (also distributed by the assignee of the present application).
A filter rod making machine of the type disclosed in the aforementioned U.S. patents to Greve and Hxc3xa4usler et al. converts a tow of filamentary filter material which is drawn from a suitable source (such as a bale of compacted filter material) and is subjected to several treatments on its way to a wrapping apparatus or unit wherein the properly processed tow constitutes a continuous rod-like filler or stream ready to be draped into a running web of filter paper, cigarette paper or the like. The thus obtained filter rod is ready to be severed in a so-called cutoff to yield a file or series of filter rod sections or mouthpieces of desired length. Such cutoff normally employs a rotary knife which repeatedly moves across the path for the filter rod while advancing with and at the speed of the rod; this ensures the making of clean cuts devoid of tears, rough edges or the like.
On its way to or in the aforementioned wrapping unit, the processed tow must undergo a compressing or condensing action in order to ensure that the cross-sectional area of each of a series of successive increments of the processed tow will match or sufficiently approximate a certain cross-sectional area which is desirable for several reasons, e.g., to facilitate and ensure proper wrapping of the filler and/or to ensure that each ultimate product (filter mouthpiece) will have a prescribed (such as circular or oval) cross-sectional outline. This is accomplished by subjecting successive increments of the running processed tow to the compressive action of a suitable implement or tool which is or which can be located close to the wrapping unit.
The treatment to which a tow of filamentary filter material is subjected in the path leading from a source (such as a bale) to the wrapping unit normally includes longitudinal stretching and simultaneous or immediately following transverse spreading (singularizing) of the filaments of the tow to form a layer of more or less parallel filaments. Such filaments are contacted by a finely atomized spray of a suitable liquid softening agent (such as triacetin) prior to entry of successive increments of the stretched, spread out and sprayed upon tow into a so-called horn which imparts to the tow the shape of a rod-like filler ready to be subjected to a further compressing or densifying or condensing treatment by the aforementioned implement; such implement normally is or can be located at the inlet of the wrapping unit.
The purpose of the atomized softening agent is to ensure that portions of neighboring filaments in the tow adhere to each other on their way through the gathering horn, during teatment by the compressing implement (finger) and/or during wrapping. Such filaments establish a maze of discrete narrow paths for the flow of tobacco smoke from the lighted end of a filter cigarette into the mouth of a smoker; this is intended to greatly enhance the filtering action, e.g., the ability of the mouthpiece to intercept nicotine and/or condensate.
The wrapping material normally employed in the wrapping unit of a filter rod making machine is a web or strip of so-caleld filter paper one marginal portion of which is provided with one or more films of a suitable adhesive (such as a hot melt) and is bonded to the other marginal portion. The overlapping marginal portions form a seam which extends longitudinally of the tubular envelope or wrapper of the finished filter rod. The filter paper is or can but need not be foraminous. The leader of the thus obtained finished filter rod is ready to be severed by the cutoff.
The implement or finger which is employed to further compress the rod-like filler of pretreated filamentary filter material downstream of the gathering horn, preferably at the inlet of the wrapping unit, is normally oriented (relative to the path for the filler) in such a way that, as seen in the direction of movement of the filler toward the wrapping unit, the filler-contacting surface of the implement slopes downwardly toward a belt conveyor which supports and advances the filler toward the wrapping unit. The shortest distance between such surface and the belt conveyor equals or approximates the desired diameter of the compressed filler.
The tow, such as a tow consisting of cellulose acetate fibers, offers a pronounced resistance to the compressing action of the implement. Therefore, the maintaining of the implement in continuous pronounced frictional engagement with the running processed tow results in the generation of pronounced heat which, in view of the high speed at which the tow is being advanced in a modern filter rod making machine, suffices to entail a melting of the filamentary material. As a rule, such partial melting of filaments at the upper side of the tow adjacent the locus of entry of successive increments of the tow into the wrapping unit is highly undesirable, primarily because the smoke filtering quality of filter mouthpieces containing partially molten filter material is inferior to the quality of mouthpieces containing filamentary filter material which does not contain molten filaments. In addition, overheated filaments can discolor and/or otherwise affect the appearance and/or other qualities of the tubular wrapper.
An object of the present invention is to provide a novel and improved method of enhancing the quality of rod-shaped fillers which contain compressible filamentary material, such as cellulose acetate fibers of the type confined in the filter mouthpieces for tobacco smoke.
Another object of the invention is to provide a novel and improved method of treating a stream of filamentary material on its way to the wrapping unit in a filter rod making machine which is designed to turn out rod-shaped filter mouthpieces for tobacco smoke.
A further object of the invention is to provide a novel and improved method of compressing a processed tow of acetate fibers in a filter rod making machine which is utilized in a production line for the making of filter cigarettes, cigars, cigarillos and analogous rod-shaped smokersxe2x80x2 products.
An additional object of the invention is to provide a method which renders it possible to avoid overheating of a processed tow of filamentary material, particularly filter material for tobacco smoke.
Still another object of the invention is to provide a method which can be practiced by resorting to relatively simply but highly effectively modified existing filter rod making machines.
A further object of the instant invention is to provide a novel and improved apparatus which can be put to use in a rod making machine to enable such machine to practice the above outlined method.
Another object of the invention is to provide a novel and improved apparatus which can be utilized for the practice of the above outlined method and can be installed in existing machines or production lines as a superior substitute for presently known apparatus.
An additional object of the present invention is to improve that portion of a machine for the making of filter mouthpieces for tobacco smoke which precedes the wrapping mechanism or unit wherein successive increments of the processed tow are draped into a running web of filter paper or the like.
Still another object of this invention is to provide a novel and improved implement which is constructed, dimensioned, configurated and operable to ensure highly satisfactory compression of a running stream or filler of filamentary material, such as cellulose acetate fibers, in or at the wrapping mechanism or unit of a rod making machine.
A further object of the invention is to provide a novel and improved machine for the making of filter rods adapted to be subdivided into filter mouthpieces of unit length or multiple unit length which can be processed in so-called tipping machines.
Another object of the present invention is to provide a method of and an apparatus for mass production of high-quality filter mouthpieces for tobacco smoke.
An additional object of the invention is to provide filter mouthpieces for tobacco smoke which are superior to those capable of being turned out at the same rate by presently known machines for the making of filter rods and filter mouthpieces for tobacco smoke.
One feature of the present invention resides in the provision of a method of processing filamentary material, particularly filamentary (fibrous) filter material for tobacco smoke. The improved method comprises the steps of advancing a compressible stream of filamentary material lengthwise in a predetermined direction along a predetermined path having at least one selected portion wherein successive increments of the advancing stream are at least partly accessible, and reducing the cross-sectional areas of successive increments in the at least one selected portion of the path. The reducing step includes at least intermittently contacting successive increments of the advancing stream by a portion of a stream compressing implement and repeatedly moving such portion of the implement relative to the at least one selected portion of the path.
The stream can contain or consist of cellulose acetate fibers.
The moving step can include vibrating the aforementioned portion of the stream compressing implement, preferably at a frequency in the ultrasonic range (e.g., between about 5 and 50 kilohertz). The vibratory movements of the aforesaid portion of the implement can have an amplitude in the range of between about 3 and 55 micrometers.
The portion of the implement can be vibrated exclusively in and counter to the direction of movement of the stream along its path, exclusively transversely of such direction, or with a component of movement in at least one of the directions longitudinally and transversely of the path.
The reducing step can include imparting to successive increments of the stream a predetermined cross-sectional outline, and such method can further comprise the step of thereafter (i.e., subsequent to completion of the reducing step) confining the stream in a tubular wrapper to thus convert the stream into the filler of a continuous rod composed of the compressed stream and of the tubular wrapper which surrounds the compressed stream. The confining step of such method can include conveying a strip of wrapping material (such as filter paper) in the predetermined direction along the path downstream of the at least one selected portion of the path, applying to one marginal portion of the strip at least one film of an adhesive (such as a hot melt), and converting the strip into the tubular wrapper including contacting the adhesive-coated one marginal portion with another marginal portion of the strip.
The method can further comprise the steps of establishing a source (such as a bale) of a continuous tow of filter material at a second portion of the path upstream of the at least one selected portion, and converting the tow into the stream in the path between the second portion and the at least one selected portion of such path. The converting step can include stretching the tow in the predetermined direction, simultaneously or thereafter or therebefore spreading the tow transversely of the predetermined direction, applying droplets of a softening agent (such as triacetin) to the filter material of the spread-out tow, and thereupon gathering the tow into the aforementioned stream.
Another feature of the present invention resides in the provision of an apparatus for processing filamentary material, such as fibrous filter material for tobacco smoke. The improved apparatus comprises means for advancing a compressible stream of filamentary material lengthwise in a predetermined direction along a predetermined path having at least one selected portion wherein successive increments of the advancing stream are at least partly exposed and accessible, and means for reducing the cross-sectional areas of successive increments of the advancing stream in the at least one selected portion of the path. Such reducing means includes a compressing implement having a portion which at least intermittently contacts the stream in the at least one selected portion of the path, and means for repeatedly moving the portion of the implement relative to the increments of the advancing stream in the at least one selected portion of the path.
The means for moving can include means for vibrating the portion of the implement at a frequency in the ultrasonic range, e.g., between 5 and 50 kilohertz. Furthermore the means for moving can include means for imparting to the portion of the implement vibratory movements having an amplitude within a range of between about 3 and 55 micrometers.
Still further, the means for moving can include means for vibrating the portion of the implement in and counter to the predetermined direction, transversely of the predetermined direction, or in a direction in which the vibratory movements of the portion of the implement have a component of movement in the predetermined direction, transversely of the predetermined direction and/or in one or more additional directions.
The aforementioned portion of the implement can be provided with a stream-contacting surface extending in the predetermined direction.
The aforementioned portion of the implement can comprise or can consist of steel, and such portion of the implement can constitute a powder metallurgically produced part.
The improved apparatus further comprises means for confining successive increments of the advancing stream in a tubular wrapper downstream of the at least one selected portion of the path. Such confining means can include a mechanism wherein the stream is draped into a running elongated web of wrapping material having an adhesive-coated first marginal portion contacting a second marginal portion to form therewith a seam extending longitudinally of the tubular wrapper.
Still further, the apparatus can comprise a source of a continuous tow of filamentary material at a second portion of the path upstream of the at least one selected portion, and means for converting the tow into the aforementioned stream in the predetermined path between the second portion at the at least one selected portion of such path. The converting means can include means for stretching the tow in the predetermined direction, means for preferably simultaneously spreading the tow transversely of the predetermined direction, means for applying droplets of a softening agent (such as triacetin if the filamentary material is fibrous filter material for tobacco smoke) to the material of the spread-out tow, and means for thereupon gathering the tow into the stream.
A further feature of the present invention resides in the provision of a method of processing filamentary material. The method comprises the steps of advancing a stream of filamentary material lengthwise along a predetermined path, and subjecting the advancing stream to a plurality of treatments in several portions of the path. At least one of these treatments includes establishing a frictional engagement between the advancing stream and at least one stream-compressing implement, and the method further comprises the step of maintaining the rise of temperature of the stream (namely that rise which is attributable to frictional engagement between the stream and the at least one implement) below a predetermined value, preferably below that value at which the filaments are likely to or actually melt.
The maintaining step preferably includes imparting to the at least one implement a high-frequency vibratory movement relative to the stream in the respective portion of the path.
The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved apparatus itself, however, both as to its construction and the modes of assembling, installing and operating the same, together with numerous additional important and advantageous features and attributes thereof, will be best understood upon perusal of the following detailed description of certain presently preferred specific embodiments with reference to the accompanying drawings.